Conventional mooring of a vessel using a single line generally involves dropping an anchor and letting the vessel weathervane to the downstream position from the anchor point. The variability of the depth must be considered in the amount of anchor line which if deployed. Consider, for example, water level varies between 100 foot depth and 400 foot depth and the anchor is set tightly when the water is at a depth of 100 feet. When the water depth moves towards 400 feet, the anchor line will either hold the vessel down until it sinks, the anchor line will be broken, or the anchor will be pulled out of the floor below the body of water. All three options are potentially bad.
Such a variability of depth occurs in situations such as sanitation ponds where the water level varies substantially over the seasons. In sanitation ponds, it is useful to moor multiple vessels on the surface of the water in specific locations for a variety of tasks. One of these tasks would be to support solar cells and pumps. These pumps can spray the sanitation water into the air for aeration and to promote the improvement of its quality. Other applications would be to support wind energy generation equipment and water quality measurement instrumentation.
The greatest benefit can be realized from equipment such as this by having the maximum number of units in the water with the tightest possible spacing. This means that the watch circle or area of movement of each unit should be as small as practical. Dense spacing and large watch circles would mean that they would tangle with one another and interfere with the operations.